The present invention relates to an improved subsea guidebase which is readily retrieved and reinstalled.
U.S. Pat. No. 3,321,015 discloses a recoverable guide base in which the guide base is made in two sections which are hinged at one side and latched together at the other side with a latching element. The guide base is assembled on the conductor casing on the platform. The latching element includes a pressure responsive element which can be remotely released so that the two sections pivot apart and thus disengage from the conductor casing.
U.S. Pat. No. 3,353,595 discloses a guide base and conductor casing which are cemented in a well bore and the casing head is connected to the upper end of the conductor casing by J slots which engage pins extending from the upper end of the conductor casing.
U.S. Pat. No. 4,181,196 discloses the recovery of the guide base, conductor casing and surface casing through the use of an explosive charge which is lowered into the well below the sea floor and a tool which engages pad eyes on the upper surface of the permanent guide base for the lifting and retrieval of the equipment after the explosive has severed the casings below the floor of the water.
U.S. Pat. No. 4,460,047 discloses a lateral connector between a subsea template and a well suspension joint in which the connector includes a ring in a housing recess with the housing secured to a template and the ring is secured in the recess by shear pins. The ring resists lateral forces on the joint until the shear pins release and then acts as a lost motion connection to allow lateral motion within the limits of the movement of the ring on the annular housing recess.
U.S. Pat. No. 4,591,296 discloses a temporary guide base cable which includes sockets that pass readily through a split latch ring on the permanent guide base as it is lowered but do not release on retrieval of the permanent guide base unless overloaded so that the temporary guide base is retrieved with the permanent guide base. In the event of overloading, shear pins in the sockets release and the permanent guide base is recovered with the temporary guide base being left on the bottom for subsequent recovery.
U.S. Pat. No. 4,611,661 discloses a permanent guide base which includes a platform portion and a gimbal portion. The permanent guide base is retrievable by the separation of the platform portion from the gimbal portion which remains with the wellhead housing and a completion guide base is installed by engagement with the external wellhead housing profile.